Real time: my gear pattern

[Mixelplix]

Having never done this before, check out my gear pattern and see if I have this screwed up.

I'm thinking it might be a bit toward the heel, indicating the pinion is too far away.

I have the factory shim under the pinion measuring .0795

 

[Mixelplix]

Second attempt by increasing backlash to .007

 

[Mixelplix]

Backlash decreased to .005

 

[landtank]

I have to reference the book to get direction but I'm thinking you need about a .002" change in the pinion shim.

 

[Pin_Head]

Pinion looks deep. Try using a .010 thinner shim.

 

[Mixelplix]

Is there any noticeable difference in the patterns due to my changes in backlash?

To me it appeared to change the heel toe distances.

Ill mess with the shims tomorrow. Thanks for the help!

Ill post more pictures after I do the adjustment.

 

[landtank]

I would suggest consistency with the back lash. Set it and check the pattern, adjust shims and repeat.

That makes it easier to track your progress.

 

[Pin_Head]

These are used gears? If so all bets are off.

 

[Mixelplix]

Brand new Sierra 4.88s

 

[landtank]

the first time setting up gears is kind of nerve racking with the cost and time involved and the possible outcome if it's not right. From what you have posted you are doing OK.

get yourself a note pad and record your shim specs and backlash with associated pictures. This way you can see what yu are dong and how it effects the pattern.

 

[Sc0-]

.007/.010 less shim and check again...

 

[Pin_Head]

PM Zuk @ gearinstalls.com


He has a good eye for that stuff.

 

[Mixelplix]

Thanks for the encouragement, Landtank.


Ill hit the garage again tomorrow and try to get a few different patterns.

 

[powderpig]

You are too deep, you do need to back off, As others have suggested take notes, I believe you are not as deep as pin suggests, but deeper than landtank suggests. It may all depends on what shims you have on hand. take your time and take deep breaths. Enjoy.

 

[Mixelplix]

Round 2:

.070 shim (down from 0795) / 006 backlash

 

[gearinstalls.com]

That 070 shim should have put it very close....instead, you now appear deeper than before. Something is not tightened down....
the 2 top pics are drive...the 2 bottom ones are coast side.
The drive is too hard(well, not that hard) on the toe(inside) and too deep in the root(for sure) of the tooth. Are you sure you have the inner race seated down fully? And did you possibly add up the shim pack wrong?
ZUK

 

[Mixelplix]

Well, let me back up.

Yesterday's pictures were taken while I had the factory 0795 shim located on the pinion. I removed that shim (or washer) from the stock pinion and put it on my new pinion, then ran the pattern.

Since the majority of the advice was to lower the pinion, tonight I separated the new pinion from the bearing, and removed the factory shim (washer).

I then measured a stack of shims at once (not individually) and put them under the inner bearing race. I'm fairly confident I had it seated fully.

Perhaps my error was trying to measure the shims as a stack, rather than individually and adding them together?

Regardless, in your opinion it appears I need less shims, correct?

 

[gearinstalls.com]

Mixel----You can't interchange pinions like that.....they are a matched set.

 

[Pin_Head]

I don't believe that he is mixing pinions. These are a new set of 4.88s.

It is very strange that the pattern looks like the pinion is deeper after using a .0095 thinner shim. Something is not right. Either the bearing isn't seated, or there is a piece of dirt in the shim stack or the measured thickness is off.

 

[landtank]

I'm not sure if this is considered acceptable but I usually slightly over tighten the pinion nut and then wrap on the pinion itself to ensure things are seated completely. I use a 1/2" drift and 3 lb hammer. The shock of the hit helps things settle in.